#include<iostream>
#include<vector>
using namespace std;
#include<algorithm>
class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        if(!nums.empty()){
            sort(nums.begin(),nums.end());
            for(int i = 0;i<nums.size()-1;++i){
                if(nums[i]==nums[i+1]){
                    return true;
                }
            }
        }
        return false;
    }
};